Category Archives: Bioenergy

Soil Requirement

J. curcas is adapted to wide range of soils and can thrive on degraded, sandy, saline soils and even on rock cervices, but shows luxurious growth on drained soils with good aeration (Dagar et al. 2006) . Although the plant can grow on low nutrient content marginal soils, such as along streams, canals, river embankments, coastal lines, along roads and railway lines, the crop however requires phosphorus and nitro­gen fertilization in order to support a high biomass production (Daey Ouwens et al. 2007). Jatropha grows best on loamy soil while as clay soils become unsuitable, if climatic conditions cause water logging. Soil pH between 5.5 and 9.0 is considered optimal for growth (Foidl et al. 1996). Nutrient availability is affected significantly by soil proprieties such as EC, pH, CaCO3, organic C, and clay.

17.3.1 Climate

Jatropha thrives well in warm weather in temperature range of 20-27 °C and can tolerate severe heat. Although vulnerable to freeze damage, Jatropha can withstand short duration light frost. In extreme cold conditions, the plant drops its leaves. Tolerance to cold temperature increases with increase in age with older trees being more tolerant. Black frost severely damages older plants and can kill young plants (Nahar and Ozores-Hampton 2007). Little rain in summers favors proper seed ger­mination. A decrease in temperature on onset of rainy season induces flowering. Jatropha can be cultivated successfully in areas with sparse to heavy rainfall (Gubitz et al. 1999). Jatropha can be grown in subtropical/tropic areas, with 200-1,500 mm rainfall per annum (The Biomass Project 2000).

17.3.2 Propagation

Seeds and plant cuttings are means of propagation. Seeds or cutting twigs can be planted directly in the field. Germination is quick and better if seeds are soaked in cold water for 24 h (Kaushik et al. 2007). Nursery-grown seedlings produce seeds earlier than direct seeded ones and also have survival rate higher than later (Daey Ouwens et al. 2007). Seedlings can be planted in the field at the onset of the rains (Heller 1996) . Taproot development in seed raised plants confers more drought resistance to them in comparison to plants raised from cuttings (Achten et al. 2007) as it enables plant to extort moisture from deeper soil stratum. In intercropping systems, the tap root also reduces competition for nutrients and water between the different crops.

Pretreatment

The first step in lignocellulose conversion to bioethanol is size reduction and pre­treatment. Pretreatment of biomass is technically challenging and is a large part of the process cost and therefore will need to be optimized prior to commercialization.

Table 20.1 Composfficm of Carbohydrate composition

representative lignocellulosic (% dry wt)

feedstocks Feedstocks Cellulose Hemicellulose Lignin

Barley hull

34

36

19

Barley straw

36-43

24-33

6.3-9.8

Bamboo

49-50

18-20

23

Banana waste

13

15

14

Corn cob

32.3-45.6

39.8

6,7-13.9

Corn stover

35.1-39.5

20.7-24.6

11.0-19.1

Cotton

85-95

5.1-15

0

Cotton stalk

31

11

30

Coffee pulp

33.7-36.9

44.2-47.5

15.6-19.1

Dauglas fir

35-48

20-22

15-21

Eucalyptus

45-51

11.1-18

29

Hardwood stems

40-55

24-40

18-25

Rice straw

29.2-34.7

23-25.9

17-19

Rice husk

28.7-35.6

11.96-29.3

15.4-20

Wheat straw

35-39

22-30

13-16

Wheat brain

10.5-14.8

35.5-39.2

8.3-12.5

Grasses

25-40

25-50

10.2-30

News paper

40-45

24-39

18-30

Sugarcane bagasse

25-45

28-32

15-25

Sugarcane tops

35

32

14

Pine

42-49

13-25

23-29

Poplar wood

45-51

25-28

20-21

Olive tree biomass

25.2

15.8

19.1

Jute fibers

45-53

18-21

21-26

Switchgrass

35-40

25-30

15-20

Winter rye

29-30

22-26

16.1

Oilseed rape

27.3

20.5

14.2

Softwood stem

45-50

24-40

18-25

Oat straw

31-35

20-26

10.1-15

Nut shells

25-30

22-28

30-40

Sorghum straw

32-35

24-27

15-21

Tamarind kernel

11-15

55-56

Water hyacinth

18.2-22.1

48.7-50.1

3.5-5.4

Menon and Rao (2012)

The purpose of the pretreatment step is increasing the surface area and porosity, lignin removal, depolymerization of hemicellulose, hemicelluloses removal, and disruption of lignocelluloses structure. Thus the cellulose component is accessible to hydrolyzing agents and reduces the crystallinity of cellulose to further facilitate hydrolysis (Balat et al. 2008).

A successful pretreatment must meet the following requirements: (1) improve formation of sugars or the ability to subsequently form sugars by hydrolysis, (2) avoid degradation or loss of carbohydrate, (3) avoid formation of by-products inhibitory to subsequent hydrolysis and fermentation processes, and (4) minimize energy input

and be cost-effective. The pretreatment stage promotes the physical disruption of the lignocellulosic matrix in order to facilitate acid — or enzyme-catalyzed hydroly­sis. Pretreatments can have significant implications on the configuration and effi­ciency of the rest of the process and, ultimately, also the economics (Hamelinck et al. 2005) . The goal of pretreatment of lignocellulosic biomass to biofuel is depicted in Fig. 20.2.

The most pretreatments are done through physical or chemical means. In order to achieve higher efficiencies, both physical and chemical pretreatments are required. Physical pretreatment is often aimed to reduce size of the biomass. Chemical pretreatment is aimed at removing chemical barriers so that the enzyme can access cellulose for microbial destruction. Each type of feedstock requires a particular combination of pretreatment methods to optimize the yield of that feed­stock, minimize degradation of the substrate, and maximize the sugar yield.

Summary

NFC as eco-friendly materials, have been emerged as an alternative to the tradi­tional glass/carbon-reinforced polymer composites. They are attractive materials for different applications like packaging, furniture, and automotive industries. Such materials have several advantages like, the low cost, acceptable mechanical proper­ties, good thermal and acoustic insulating properties, availability, CO2 sequestration enhanced energy recovery, etc. The properties and performance of the final natural fiber composites depend on the properties of both the matrix and filler as well as their interfacial bonding.

Both physical and mechanical treatment processes were performed on the cellulosic fibers to enhance the interfacial bonding characteristics of the natural fiber composites. Different factors and criteria can affect the performance of the produced natural fiber composites. Some of these criteria affect the selection of the composite constituents (matrix and fillers), whereas others can determine the final performance of the produced product of such materials. Wide range of physical, biological, mechanical, environmental as well as economic properties of the poly­mer composite have to be investigated to optimize and widen their potential applications.

The petroleum derived thermoplastics and thermosets are widely used for pro­ducing different natural fiber composites oriented for various industrial applica­tions. The potential and competitiveness of the palm fiber was proved for different industrial applications particularly the automotive ones. It can be considered that date palm fiber is one of the most available natural fiber types all over the word. It can be utilized with different polymer matrices to produce satisfactorily strong composites. The effect of the chemical treatment of the date palm fiber had been proven to increase its final mechanical properties as well as its reinforced polymer composites.

1.5 Conclusions

The NFRPC became recently a valuable type of materials due to their desirable eco­friendly characteristics. Adopting the natural wastes and resources in finding alter­native low cost materials can enhance the industrial sustainability as well as reducing the environmental pollution. Biodegradability, low cost, low relative density, and the high specific strength characteristics are the main added value steps of the natu­ral fiber composites. Widening the application of such materials can contribute to the human living standards as well as the green environmental indices. Many poten­tial natural fiber types are still undiscovered due to the improper evaluations of such fibers. Date palm fiber is one of the most competitive fiber types for producing natu­ral composites. Several studies had demonstrated its capability to produce different composites with various thermo plastics and thermoset polymers. Proper fiber treat­ment can enhance the role of date palm fiber in supporting the natural composites with more desirable characteristics to contribute the sustainable industrial applica­tions. Further research is required to improve the natural fiber performance and to overcome their drawbacks like the moisture absorption, inadequate toughness, and reduced long-term stability for outdoor applications.

Acknowledgment The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding this work through research group no RGP-VPP-133.

Potential Areas of Abaca-Fiber Application

1. As per the “End-of-Life-Vehicle Regulation” by the European parliament, the natural fibers like abaca will be used in designing and manufacturing of car com­ponents which will enable their safe disposal and recyclability at the end of their life. Moreover, research is being conducted to develop needle punched abaca fabric for possible use in the production of padding and backing for automotive industry.

2. Abaca fiber has a great potential in ship building, aeronautics, and construction of high-rise buildings.

3. Compared to cordage made of synthetic fibers, the abaca fibers are biodegrad­able and therefore can be dumped without any environmental hazard. Moreover, the poor reflecting ability of abaca ropes makes them suitable for use in American movie-making industry as they do not reflect on exposure to klieg lights.

4. The use of abaca fibers in preparation of sausage casings has a great potential due to their inability to dissolve in boiling water besides being free from any health hazard (if eaten mistakenly)

5. Abaca fibers offer a good and easily available substitute for wood pulp, thereby reducing the pressure on the conventional sources of pulp-yielding plants. A good example is provided by Japan where the Japanese currency (¥10,000, 500, and 1,000) has been found to contain about 60 % abaca components. Similarly there are reports from China where a huge increase in demand for abaca fibers is expected to meet the requirements for recycling waste paper. Similar example is provided by the European company “the PH Glatfelter” who has produced the disposable K-cups made of special filter paper containing 100 % abaca fiber.

6. Abaca fiber also has great potential in the production of world-class furniture like sofas, tables, chairs, beds, etc.

7. The production of products like abaca soap or lotion with anti-aging or therapeu­tic properties will also revolutionize the cosmetic industry.

8. It also offers great potential for textile industry as blending of abaca fibers with other natural fibers like silk can be used to produce fabrics of excellent quality, e. g., the manufacturing of denim by Asiatex (The Asia Textile Mills, Inc.) in Calamba City by bending of abaca (40 %) and polyester (60 %). Other fabrics like shirts, blouses have also been developed and research is being conducted to pro­duce fabrics of extraordinary qualities like antimicrobial and “stay cool and fresh.”

9. Abaca-reinforced composites have a good potential for use in automotive plastics.

Hydrophobic-Oleophilic Property

Kapok fiber contains the pectin and wax substances that contribute to its hydro­phobic-oleophilic characteristic. On the glass slide coated with kapok extract, the diesel drop and water drop will show a different spreading radius and contact angle. The diesel drop can spread out rapidly, and in contrast, the water drop cannot spread out on the glass slide. As a result, a large spreading radius and small contact angle are observed for diesel drop, whereas a large contact angle is visualized for water drop, demonstrating that the oil is a wetting liquid for kapok fiber and the water is a non-wetting liquid for kapok fiber (Lim and Huang 2007). The static and dynamic contact angle of kapok fibers with different kinds of liquids such as vegetable oil, used oil, and engine oil is also investigated. It is found that kapok fiber is an excel­lent oleophilic and hydrophobic fiber with the contact angle of kapok fiber to water of 139.55o, but is less than 60o to various kinds of oil. The contact angle of kapok to water is constant as time flies. All the oil liquids on the kapok fibers have the quick spread rates, and the spread curves are similar though the spread rates varied with viscosity and surface tension of the liquids (Sun et al. 2011). This hydrophobic — oleophilic characteristic can be tuned by solvent treatments. Our study reveals that for untreated and NaClO2-treated kapok fiber, different wetting phenomenon can be observed using water drops, with a large contact angle of 116o and a large spreading

image35

Fig. 6.2 Pictures of water droplet (dyed with methylene blue) on (a) raw, (b) treated, and (c) superhydrophobic kapok fiber surface; oil droplet (dyed with oil red O) on (a1) raw, (b1) treated, and (cl) superhydrophobic kapok fiber surface (Wang et al. 2012b) (Copyright 2012, reproduced with permission from Elsevier)

radius for untreated and NaClO2-treated kapok fiber, respectively (Fig. 6.2) (Wang et al. 2012b). Here, another observation should also be mentioned. Before and after collecting the oils from water, the kapok fiber may float steadily on the water sur­face due to its light density and hydrophobic-oleophilic properties, a useful charac­teristic for oil spills cleanup. In addition to the thin hydrophobic plant wax layer covered on the surface of kapok fiber, the hydrophobic-oleophilic characteristic is also related to its micro-nano-binary structure (Zhang et al. 2013).

Final Remarks

One third of the total primary energy is contributed by straw in sugarcane as a crop. Sugarcane also possesses some characteristics which are very similar to widely used bagasse. This makes it a very good fuel to bagasse supplement. It can contrib­ute to surplus power generation in the mills. For the second generation production of biofuels, straw can be efficiently used. An excellent opportunity is provided in Brazil in order to increase the fast implementation of management system of green cane to increase sugarcane energy performance, sustainability of the production of ethanol, as well as the economics. But its use is incipient, still. This is due to lack in the long-term experience with collection and use of straw along with the uncertain­ties in the processing, storage, and collection costs (Leal et al. 2013).

The benefits imparted by agronomic characteristics are pretty clear, but the quan­tification is difficult although their magnitude is analyzed in different situations. The minimum amount for the assurance of ground protection against erosion has not been estimated. A significant difference is contributed between burned cane, which is in bare soil and unburned cane, with straw mulch on the ground in the water and soil losses. Literature revealed a consistent increase concerning the con­tent of soil carbon in the management of green cane with all straw left in the fields in comparison with burned systems of cane. A wide variation has also been shown in the results as it depends on climate and soil characteristics as well as the history of land use.

It has been noted that straw blanket imparts positive as well as negative impacts on the biota. Positive effects on macrofauna in the soil mainly include ants and worms, whereas the negative one includes increase in population of pests. The effect of inhibition of weed by straw mulch has also been confirmed by several authors for some of the species and has been found neutral for others. This data helped in gath­ering information about the magnitude of different impacts imparted by straw mulch left on the ground after harvesting the unburned sugarcane. This helped in assess­ment of optimum straw that should be left in the field to take advantage of the agro­nomic and industrial benefits. There are many variables that affect various benefits that were included in the evaluation. These variables include soil and climate char­acteristics, local topography, varieties of sugarcane and agricultural practices, etc.

At this time it is not possible to define proper amount of straw that should be left on the ground.

Best approach would be initial concentration on the erosion of soil and dynamics of soil carbon. These are associated with both economic and environmental benefits. Economic benefits include fertility of soil, yield of the crop, and cost of the produc­tion, whereas preservation of natural resource, crop sustainability, and sequestration of carbon are involved in the environmental benefits. Finally, it is significant to pin point the viability of integration of technologies of second generation in future. This involves conventional distillery of sugarcane which increases the yield of biofuel per unit area cropped and the efficiency of energy. This requires the use of straw fraction that results from unburned harvesting of cane.

Light

The key ingredient to initiate photosynthesis is light as it is involved in the conver­sion of carbon dioxide to carbohydrates. As compared to higher plants, algae require relatively low intensity of light for proper development. Solar waves are

the primary source of light. Only 43-45 % of the total solar radiations are involved in commencement of photosynthesis. These radiations are termed as PAR or Photosynthetically Active Radiation. About 27 % of PAR is converted to carbohy­drates. The rate of biomass growth can be established by considering the following relation:

P = aE. l

where P is the rate of production of dry algae and is measured in g/m2/day, E is the efficiency of photosynthesis, I denotes light energy in kcal/m2/day, and the symbol a represents the conversion coefficient (g/kcal).

The light source in the cultivation system can be either natural, artificial, or com­bination of different light sources. The cheapest source is the solar energy, which is utilized in open pond systems, which require a large area for construction and have a higher contamination risk. In closed systems, fiber optics and solar concentrators can be used to maximize the effect of sunlight. As compared to fluorescent lamps, LED lights are shown to be more economically stable.

13.2.1.4 Nitrogen

Being the main constructing element of proteins and nucleic acids, nitrogen plays a significant role in algal metabolism.

13.2.1.5 Phosphorous

This element is used in the form of phosphates because if it is present in any other state, it may become unavailable to the algae due to its ability to combine with other metallic ions, which results in precipitation.

13.2.1.6 Additional Nutrients

Apart from the above-mentioned nutrients, trace amount of vitamins and metals like sodium, calcium, magnesium, manganese, zinc, copper, iron, and molybdenum are also required for efficient growth of algal culture.

13.2.1.7 Space

Unlike other organisms, algae are very versatile and do not require arable land for productive growth. They can be cultivated in ponds, water bodies, and even reactors. Issue of appropriate space is not a concern and does not put a strain on the budget or available resources.

Optimization of Parameters for Chemical Activation Reaction

The utilization of renewable and cheaper precursors to prepare activated carbon produces useful and economically feasible adsorbent but also contributes towards minimizing the solid wastes. The preparation method can be optimized to deter­mine the effect of the main parameters associated with the process are: Impregnation ratio, activation temperature, acid concentration, activation time, the precursor materials nature, the activation type (chemical and physical activa­tion), and pyrolysis temperature, all these affect the properties of the resulting activated carbon (Girgis and El-Hendawy 2002; Haimour and Emeish 2006; Diao et al. 2002).

The processing conditions are generally expressed in terms of some properties, among which: surface area, cation-exchange capacity (CEC), phenol and methylene blue, bulk density and adsorption efficiency towards iodine are frequently consid­ered (Vernersson et al. 2002; Yang and Lua 2006; Haimour and Emeish 2006). However, methylene blue is the most accepted probe molecules for the determina­tion of the ability of sorbent for the removal of large molecules whereas the iodine number shows indication on microporosity and consequently on the specific surface area of the sorbent materials (Baccar et al. 2010). Therefore, to determine the most important factor and their regions of interest it is essential to study these factors and their effects on the production of activated catalyst.

Experimental design technique is an important tool which provides statistical models in understanding the interactions among the parameters that have been opti­mized (Alam et al. 2007). The major benefit of using Response Surface Methodology (RSM) is to reduce the number of experimental trials required to evaluate several parameters and their interactions (Lee et al. 2000). RSM is a collection of statistical and mathematical techniques useful for developing, improving and optimizing pro­cesses. RSM involves three main stages: (1) design and experiments, (2) response surface modeling through regression, (3) optimization (Myers and Montgomery 1995). Based on this central composite design (CCD), quadratic models were devel­oped. The analysis of variance (ANOVA) on each experimental design response was recognized from them (Ahmad and Hameed 2010). Previously RSM was applied for the preparation of activated carbons using precursors such as Luscar char (Azargohar and Dalai 2005), Turkish lignite (Karacan et al. 2007), and olive-waste cakes (Bagaoui et al. 2001).

Conclusions & Future Endeavor

J. curcas owing to its remarkable features appears to be a suitable valuable option to meet energy demands world. Low technology inputs are requirements during cultivation step, where most of the management actions are done manually (pruning and harvesting, mainly), to harness oil reduces the investment required to generate a unit quantity of biofuels.

Multiple energy carriers of Jatropha plants and oil expelled from its seeds are not only useful in mitigating the environmental pollution but also support for employ­ment generation and entrepreneurship development. Apart from Jatropha use as potential energy crop, industrial application and soil conservation measures can also promote its cultivation on the barren and unused land. As energy crop, blending with petro-diesel and proper processing has already demonstrated its use as an alter­native fuel in motive and stationary diesel engines. Proper commercialization and utilization of by-products of biodiesel such as press-cake and glycerine oil cake can make Jatropha cultivation and oil production economically more feasible.

A better overall efficient development of J. curcas production system can be achieved, if knowledge gulf regarding fundamental agronomic characteristics, employment of best cultivation and management practices, the improvement of energy carriers and processing of oil protocols and the input/output balances at all these stages are addressed into. A deep analysis of cultivation processes will help in understanding intercropping and monoculture growth variables as well as looking for sustainability indicators in these two production systems.

A better in-depth understanding of the eco-physiology of the plant is required so to gain insight into its nutrient requirements for maximum net primary productivity and oil production, nutrient cycling, impact on biota of soil (Achten et al. 2008), plant-soil relationship, and foliar nutrient content of Jatropha (Daey Ouwens et al. 2007; Chaudhary et al. 2008) which is essential for domestication of the plant, its water use efficiencies, its potential and actual energy.

Apart from these mentioned concern, also environmental impact assessments have not been carried out exhaustively yet (Achten et al. 2008). Impacts on soil structure and its water-holding capacity, organic content and soil biological activity needs detailed investigation as well. Research for understanding plant energy efficiency under different agro-climatic condition and to improve its yield needs to be carried out (Daey Ouwens et al. 2007).

Jatropha bioenergy development has many potential benefits although having some negative impacts also. Development of this sector calls for execution of well balanced policies which can reduce the negative effects and maximize positive ones. Of positive effects some are:

1. Agricultural output diversification

2. Higher income for farmers

3. Poverty reduction

4. Rural development stimulation,

5. Employment in rural areas

6. Infrastructure development

7. Increased investment in land rehabilitation

8. Lower GHG emissions

9. Generation of new revenues from agricultural residues, wood use, and from carbon credits

On the other hand, some potential negative effects are:

1. Replacement of subsistence farmland with energy crops will result in reduction in local food availability.

2. Increase in deforestation to meet land demand for energy crops will lead to forest ecosystems degradation and decrease in biodiversity as well.

3. Degradation of soil fertility and quality due to intensive cultivation of bioenergy crops.

4. Pollutants as well as GHG emissions will register an increase.

5. Modifications to requirements for vehicles and fuel infrastructure.

Nonetheless, with the current emphasis on alternative renewable fuels due to the soaring fossil energy prices as their reserves continue to dwindle and the per­spective on global climate change, the potential role of Jatropha to meet energy services of world will warrant it beyond doubt to be one of the energy plants of future.

Lin ear Density

The linear density of bamboo fiber is calculated to be 1.44 (Erdumlu and Ozipek

2008) . It is approximately one eighth of the density of mild steel whereas its tensile strength is higher than mild steel. Hence this fiber can be used as an alternate of plastic fibers for formation of many materials (Jindal 1986). Linear density of auto­claved bamboo fiber reinforced cement composites is 1.3 g cm-3 (Coutts and Ni

1995) . Bamboo zephyr boards (BZB) exhibit less thickness and low density under dry wet conditioning cycles (Nugroho and Ando 2000). The density decreases with increase in amount of bamboo fibers in short bamboo fiber reinforced epoxy com­posites with varying fiber content (Rajulu et al. 2004). The linear density of BZB exhibits a huge effect on moduli of elasticity and rupture, internal bond strength, water absorption, and thickness swelling. The linear density is not seen to have any effect on linear expansion (Nugroho and Ando 2000).